The present invention pertains to novel calcium dialuminate and hexaluminate ceramic structures in the form of blends, laminates and composites. The ceramics of the invention exhibit relatively low levels of thermal expansion, high strengths and good thermal shock resistance over wide temperature ranges.
Due to properties such as general strength, chemical inertness, temperature stability and electrical and thermal insulating capacity, ceramics have enjoyed wide commercial usage. Such applications include cookware, spark plug insulators, abrasive wheels, refractory linings, chemical processing, heat exchangers, filters, and automotive substrates, to name a few. However, many of the ceramic materials currently employed do not capably operate in extremely high temperature environments, such as above 1500.degree. C., or in environments where exposure to very large thermal gradients, such as between 25.degree. C. and 1700.degree. C., is required. Other ceramic materials capable of operating in such harsh environments need to be developed. The present invention is directed to this end.